Fuel cell

ABSTRACT

In a fuel cell comprising (1) a generator cell having a fuel gas (hydrogen gas) chamber, an oxidizing gas (oxygen gas) chamber and an electrolyzing solution chamber (2), a fuel gas circulating circuit for supplying fuel gas to the fuel gas chamber of said generator cell, (3) an oxidizing gas circulating circuit for supplying oxidizing gas to the oxidizing gas chamber of said generator cell, and (4) an electrolyte circulating circuit for supplying an electrolytic solution to said electrolyzing chamber, the improvement characterized in that a means for regulating the concentration of the electrolytic solution at a constant value is provided on said electrolyzing chamber and a means for removing the formed water from each of said gas chambers, a means for regulating simultaneously the gas pressures in both of said gas chambers, and a means for keeping constant the temperature of said electrolytic solution are provided on each of said gas chambers.

This is a division of application Ser. No. 456,993, filed Apr. 1, 1974now abandoned.

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

This invention relates to a fuel cell, e.g., a hydrogen-oxygen type fuelcell, comprising (1) a generator cell having a fuel gas chamber, anoxidizing gas chamber and an electrolyzing solution chamber, and (2)fuel gas and oxidizing gas circulating circuits for supplying the fuelgas and the oxidizing gas to the fuel gas chamber and to the oxidizinggas of said generator cell.

2. PRIOR ART

One of the problems as to the fuel cell is to provide a system capableof removing the formed water from the generator cell during thegenerating operation and discharging the removed water out of the fuelcell. It is the usual practice to remove the formed water from theinterior of the generator cell by taking out the formed water in theform of steam using the carrier gas from the gas chamber side of eachelectrode face.

Another problem is a necessity to keep constant the concentration of theelectrolytic solution irrespective of the change of the operatingconditions, as the concentration of the electrolytic solution greatlyinfluences the properties of the fuel cell. On the other hand, a porousgas diffusing electrode is used in the fuel cell, and it is necessary inorder to operate the fuel cell stably for long period of time to keepthe gas chamber side of the electrode always in the dried state.Accordingly, larger amounts of water larger than that of the formedwater must be removed during the generating operation, but this resultsin the reduction of the amount of electrolytic solution, i.e., theincrease of the concentration thereof. To solve this problem, suchamounts of water as deducting that of water formed during the generatingoperation from that of water separated from the fuel cell by abovedescribed process, i.e., excess amounts of water deducted from theelectrolytic solution, must be returned to the electrolytic solution, orclean water must be replenished to the electrolytic solution to keepconstant the concentration thereof.

A further problem of the fuel cell is the necessity of balancing thepressure of hydrogen or oxygen gas with that of the electrolyticsolution thereby to prevent the blowing of the gas into theelectrolyzing solution chamber or inversely to prevent the penetrationof the electrolytic solution into the gas chamber, for the purpose ofkeeping a three phase zone. If the pressure balance between the gas andthe solution is destroyed, each gas blows through the gas chamber intothe electrolyzing solution chamber, or the electrolytic solutionpenetrates through the electrolyzing solution chamber into the gaschamber, thus making it impossible to maintain the three phase zone.

A still further problem of the fuel cell is the necessity to keepconstant the operation temperature of the fuel cell by removing theinternal heat generation which is caused by the voltage drop due to thepolarization potential of each electrode and the resistance of theelectrolytic solution. One of the conventional temperature controllingmethods is to flow intermittently cooling water by the operation of anelectromagnetic valve. This method, however, is not favorable, since theamplitude of the temperature change becomes remarkable, and, moreover,the electromagnetic valve must be operated frequently to decrease theamplitude of the temperature change, thus shortening the life of theelectromagnetic valve. Another method is to use a proportional valvesuch as is used in the ordinary plant, but proportional valves are notsuitable as to shape, size and weight. Furthermore, both methods requireelectric operation, which consumes the electric power to reduce thetotal generating efficiency and requires a temperature detector, arelay, and an electric amplifier. Many of such electric instruments makeintricate the structure of the fuel cell generating apparatus.

OBJECTS OF THE INVENTION

Therefore, an object of this invention is to arrange various members orinstruments in a fuel cell not to accumulate the formed water or theleaked gas in the electrolyzing solution chamber.

Another object of this invention is to carry out both the discharge ofthe formed water and the return thereof to the electrolyzing system bymaking use of the pressure of hydrogen gas or oxygen gas without a pumpor the like special means.

A further object of this invention is to keep the concentration of theelectrolytic solution at an approximately constant value by detectingthe concentration of the electrolytic solution as measuring thereduction of the amount thereof, and replenishing such amount of cleanwater as corresponding to the concentration or amount of theelectrolytic solution to an electrolyzing solution tank.

A further object of this invention is to keep the temperature (operatingtemperature) of the electrolytic solution at an approximately constantvalue by absorbing continuously the internal heat generation in the fuelcell with the circulating electrolytic solution.

A still further object of this invention is to regulate both pressure ofthe hydrogen gas chamber and that of the oxygen gas chambersimultaneously with a single pressure controller to exhibit an equalvalue.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a fuel cell according to this invention,

FIG. 2 is a schematic view of another fuel cell according to thisinvention,

FIG. 3 is an enlarged cross section of a water tank in the fuel cellshown in FIG. 2,

FIG. 4 is a schematic view of a controller for the concentration of theelectrolytic solution,

FIG. 5 is a cross section of a controller for the temperature of theelectrolytic solution,

FIG. 6 is a characteristics curve of wax used in the temperaturecontroller shown in the FIG. 5,

FIG. 7 is a graph showing a relation between the temperature of theelectrolytic solution and amount of cooling water in the temperaturecontroller shown in the FIG. 5,

FIG. 8 is a systematic view of a fuel cell having the pressureregulating means according to this invention,

FIG. 9 is a longitudinal cross section of the pressure controller meansshown in the FIG. 8, and

FIG. 10 is a partly enlarged cross section of another pressurecontroller means shown in the FIG. 8.

PREFERRED EMBODIMENTS OF THE INVENTION

Now, more particular embodiments of this invention will be describedwith reference to the accompanying drawings.

Referring to the FIG. 1, pluralities of oxygen and hydrogen gas chambers2 and pluralities of electrolyzing solution chambers 3 are provided in agenerator cell 1. Oxygen and hydrogen electrodes (not shown) are alsoprovided in the generator cell. A gas circulating circuit 4 suppliesoxygen or hydrogen gas to either the oxygen or hydrogen gas chambers 2.Another gas circulating circuit (not shown) is arranged in parallel tosaid circuit 4 to supply whichever gas is not supplied by the showncircuit. Numeral 5 indicates a gas cooler of the gas circulating circuit4 provided at the lower part of the generator cell 1, and numeral 6indicates a gas circulating pump. The circulating gas is cooled in thegas cooler 5, introduced into the upper part of the generator cell 1 bythe gas circulating pump 6, and passed through the generating cell 1downwards to return to the gas cooler 5. Moisture formed in thegenerating cell 1 is carried by the circulating gas into the gas cooler5, and condensed therein to drip in a formed water tank 7, which isarranged below the gas cooler 5.

An electrolytic solution circulating circuit 8 for supplying theelectrolytic solution to the electrolyzing solution chamber 3 of thegenerator cell 1 is equipped with an electrolyzing solution tank 9 andan electrolytic solution circulating pump 10. The electrolyzing solutiontank 9 is formed to have therein a free liquid surface. The electrolyticsolution flows through the electrolyzing solution tank 9, theelectrolyzing solution circulating pump 10, and the electrolyzingsolution chamber 3 upwards. A clean water tank 11 is provided on theupper part of the electrolyzing solution tank 9, and the clean water issupplied to the electrolyzing solution tank 9 from time to time tocontrol the concentration of the electrolytic solution therein.

In such a fuel cell, the gas leaked into the electrolyzing solutionchamber of the generator cell 1 is carried by the electrolytic solutionflowing through said chambers upwards into the electrolyzing solutiontank 9, and it is easily separated and released from the electrolyticsolution at the free liquid surface. As the direction of the rising gasagrees with that of the flowing electrolytic solution, the leaked gas isnot retained in the generator cell 1 and in the way of the electrolyzingsolution pipe between the generator cell 1 and the free liquid surfacein the electrolyzing solution tank 9.

Besides, the circulating gas is forced to pass through the gas chambers2 in the generator cell 1 downwards, and accordingly both theelectrolytic solution penetrating into the gas chambers of the generatorcell 1 and the moisture condensed in the neighbor of the gas outlet ofthe generator cell are not retained in the generator cell 1 and in theway of the gas pipe between the generator cell and the gas cooler 5,since the direction of the circulating gas flow is the same as that ofthe electrolytic solution flow or the moisture flow. The formed watercontained as the vapor in the gas is condensed in the gas cooler 5,separated therein from the carrier gas, and dripped into the formedwater tank 7.

Thus, the above described conditions for keeping always the three phasezone are satisfied by the structure of the fuel cell according to thisinvention.

Referring to the FIG. 2, the clean water tank 11 may be connected to theformed water tank 7 via a return pipe 12, whereby the formed water canbe used as the water for regulating the concentration of theelectrolytic solution. In such a case, the inner pressure of the gascooler 5 or that of the gas circulating circuit 4 is set at such a valuethat the formed water rises from the tank 7 through the formed waterreturn pipe 12 to the formed water return tank (clean water tank) 11 dueto a difference between the pressure in the gas cooler 5 and the innerpressure of the clean water tank 11 (atmospheric pressure). That is tosay, the pressure in the gas cooler 5 is set at a value h mm Aq higherthan the atmospheric pressure, assuming that a height between a liquidsurface in the formed water tank 7 and a water inlet 13 of the formedwater return tank 11 is h mm.

Numeral 14 indicates a float switch operated "on" or "off" state inaccordance with the liquid level in the formed water tank 7, and numeral15 indicates an electromagnetic valve opened or closed by said floatswitch 14. In order to prevent the leakage of the gas in the gas cooler5 into the formed water return tank 11, the electromagnetic valve 15 isset closed where the operating level of the float switch 14 is below apredetermined level, and the outlet of the formed water is provided atthe lowest part of the formed water tank 8. Excess amount of formedwater is discharged from an overflowing opening 16 provided on theformed water return tank 11. The formed water in the formed water returntank 11 is replenished into the electrolyzing solution tank 9 inaccordance with the concentration and level of the electrolytic solutionin the formed water return tank 11, as shown in FIG. 4 and furtherdescribed hereinafter. In this embodiment, special conveying means otherthan gravity is not required to supply the formed water to theelectrolyzing solution tank 9.

In the example of the formed water tank 7 in the FIG. 2, the dischargeof the formed water is regulated by both the float switch 14 and theelectromagnetic valve 15, but a float valve 17 opening or closingaccording to the level in the formed water tank 7, as shown in the FIG.3, can be used in lieu of the float switch 14 and the electromagneticvalve 15.

Thus, the formed water can be discharged by the difference between thepressure in the gas cooler and that in the formed water return tank, andon occasion, can be returned, as the replenishing water, to theelectrolytic solution in accordance with said pressure difference.Accordingly, the formed water can be discharged or returned to theelectrolytic solution without using any special means. Besides, the fuelcell according to this invention has the minimum movable parts andconsumes the minimum energy by itself.

Referring to the FIG. 4, the concentration of the electrolytic solutioncan be easily regulated by replenishing the clean water thereto from theformed water return tank (clean water tank) 11 according to the level inthe electrolyzing solution tank 9. The generator cell 1 is schematicallyshown in the FIG. 4, and comprises the oxygen gas chamber 18, thehydrogen gas chamber 19, the electrolyzing solution chamber 20, ahydrogen electrode 21 and an oxygen electrode 22. The electrolyzingsolution tank 9 is filled with the electrolytic solution except for anair layer 23 which is communicated to the atmospheric air via a breezer24.

Numeral 25 indicates a pipe for replenishing water from the clean watertank 11 to the electrolytic solution, and an electromagnetic valve 26 isprovided in the way of the water replenishing pipe 25.

The electromagnetic valve 26 is actuated by a level switch 27 which isoperated "on" or "off" state in accordance with the liquid level in theelectrolyzing solution tank 9. That is to say, if the level in theelectrolyzing solution tank 9 is lowered excessively, theelectromagnetic valve 26 is opened to replenish water from the cleanwater tank 11 to the electrolyzing solution tank 9. Once the level inthe electrolyzing solution tank 9 is restored to the desired level, theelectromagnetic valve 26 is closed. In such a case, the clean water canbe replenished by gravity by providing the clean water tank 11 on theelectrolyzing solution tank 9.

As the concentration of the electrolytic solution is detected by thelevel in the electrolyzing solution tank 9, the detection work is veryeasy and the regulation of the concentration can be carried out only byreplenishing the clean water to the electrolytic solution in accordancewith the concentration. Besides, as gravity is made use of to replenishwater in the electrolytic solution, special pump means and power sourceare not required. Further more, the formed water in the fuel cell can beused as the replenishing water, thus making the fuel cell compact andeconomical. In addition to that, the regulation of the concentration ofthe electrolytic solution can be carried out ever stably withoutinfluence of the ambient temperature and the contamination of theliquid.

The level switch and the electromagnetic valve 26 used for replenishingthe clean water to the electrolytic solution can be replaced with afloat valve 28 provided in the clean water tank 11, as shown by thedotted line, which opens or closes in accordance with the level in theelectrolyzing solution tank 9. This structure makes the fuel cell morecompact and eliminates the need for a power source for the operation ofthe electromagnetic valve.

In order to remove continuously the internal heat generated in the fuelcell and to keep constant the temperature of the electrolytic solution,a water cooling pipe 29 is provided in the electrolyzing solution tank9, as shown in the FIG. 5. A regulator valve means 30 is provided in thewater cooling pipe 29 for regulating automatically the amount of thecooling water.

In the FIG. 5, a casing 31 for the regulator valve means 30 is formed asa hollow cylinder, a shielding plate 32 is fixed to one end thereof, anda cover plate 33 is attached to the other end. This casing 31 isattached to the electrolyzing solution tank 9 by a bolt 34. Both acooling water inlet 36 and a cooling water outlet 37 are arranged atmutually different positions on a center hole 35 of the casing 31 andcommunication therewith. A valve 39 sliding axially on the center hole35 and opening or closing an opening 38 between the cooling water inlet36 and the cooling water outlet 37 is provided in the center hole 35.The valve 39 is biased towards the closing direction by a spring 40.Numeral 41 indicates a valve rod of the valve 39. A handling rod 42 foropening the valve 39 penetrates slidably through a bush 43 attached tothe shielding plate 32. A heat sensitive body 44 for measuring thetemperature of the electrolytic solution in the tank 9 is attached tothe bush 43. The body 44 is composed of a chamber 45 containing waxhaving the volume expansion characteristics shown in the FIG. 6, adiaphragm 46 serving as one wall of said wax chamber 45, and a chamber47 containing transmitting medium (grease) for transmitting theamplified operation of the diaphragm 46 to the operating rod 42. That isto say, one end of the operating rod 42 is confronted with the valve rod41 and another end is confronted with the diaphragm 46 of the heatsensitive body 44.

Suitable sealing means is applied not to cause the leakage of thetransmitting medium in the chamber 47 through an aperture between theoperating rod 42 and the bush 43. A spring 48 having a repelling forcesmaller than that of the spring 40 biases the operating rod 42 away fromthe valve rod 41.

Both the shielding plate 32 and the bush 43 are made from heatinsulating material so that the heat sensitive body 44 is not influencedby the cold water and atmospheric air. The valve rod 41 is screwed tothe valve 39 to adjust the relative position to the latter and toregulate the temperature at the opened or closed state, i.e., thepredetermined temperature of the electrolyzing solution.

The operation of the fuel cell thus formed will be described below. Whenthe temperature of the electrolyzing solution is elevated by theinternal heat generation of the electrolytic solution in the fuel cell1, the wax in the chamber 45 of the heat sensitive body 44 expands inaccordance with the volume expanding property as shown in the FIG. 6 tothrust the diaphragm 46. This motion of the diaphragm 46 decreases theaxial cross section of the grease chamber 47 and the axial stroke istransmitted to the operating rod 42 as amplified. The operating rod 42is actuated against the repelling force of the spring 48 to contact thevalve rod 41, and the valve rod 41 opens the spring 39 against therepelling force of the valve 40. Thus, the cooling water is passedthrough the cooling water pipe 29 as shown in the FIG. 7, to coolcontinuously the electrolytic solution. If the temperature of theelectrolytic solution is lowered below the predetermined temperature,the valve 39 is closed to stop the supply of the cooling water to thecooling water pipe 29. On the other hand, if the temperature of theelectrolytic solution is elevated above the predetermined temperature,the valve 39 is opened with the suitable opening degree to supply thenecessary amount of cooling water.

As described above, amount of the cooling water supply to anelectrolytic solution heat exchanger can be regulated proportionallyaccording to this invention, thus the temperature of the electrolyticsolution can be kept constant exactly. This electrolytic solutiontemperature controller does not require any electric accessories such asan electromagnetic valve, so that the consumption of the electric poweris not caused to decrease the generating efficiency of the fuel cell andthe structure of the fuel cell is made simplified and compact to reducethe total weight. Besides, the temperature control is easily carriedout.

The FIG. 8 shows a schematic view of the fuel cell provided with apressure controller means 50 in order to keep a balance between thehydrogen or oxygen gas pressure and the electrolytic solution pressure.In the FIG. 8, the fuel cell 1 is shown as composed of the oxygen gaschamber 18, the hydrogen gas chamber 19, the electrolyzing solutionchamber 20, the hydrogen electrode 21, and the oxygen electrode 22. Ahydrogen gas consuming system 51 and an oxygen gas circulating system 52are arranged mutually symmetrically. The high pressure hydrogen andoxygen gasses are reduced by a pressure controller means 50 hereinafterdescribed, supplied to the gas chambers 18 and 19 of the generating cellvia ejectors 53 and 54, and consumed therein in amount corresponding tothe electric power generated. In such a case, both the pressure in theoxygen gas chamber 18 and that in the hydrogen gas chamber 19 arerequired to be kept at the constant and equal value corresponding to theelectric power generated. The pressure controlling means 50 is formed tosatisfy such requirements as shown in the FIG. 9 and FIG. 10.

In the FIG. 9, numerals 51 and 52 indicate the hydrogen gas consumingsystem and oxygen gas consuming system, respectively, and numerals 55and 56 indicate the hydrogen gas supplying system and the oxygen gassupplying system, respectively. The pressure controlling means 50 isprovided between both said gas consuming systems 51 and 52 and both saidgas supplying system 55 and 56, and constructed to controlsimultaneously both pressures. That is to say, a pressure controllingspring chamber 63 formed by a pair of diaphragm 62 and 62' is providedon a middle part of a hollow casing 61, and a pressure controllingspring 64 is contained in said chamber 63. A pair of pressurecontrolling valve mechanisms for the gas consuming systems 51 and 52 issymmetrically provided at both sides of the pressure controlling springchamber 63.

One of the pressure controlling valve mechanisms will be described.Numeral 65 indicates a gas inlet connected to the gas supplying system55, and numeral 66 indicates a gas outlet connected to the gas consumingsystem 51. A valve 67 opens or closes an outlet opening 68 whichcommunicates with the gas inlet 65 and the gas outlet 66. The valve 67is attached on a valve rod 69 which is always in contact with thediaphragm 62, and it is biased towards the valve seat of the outletopening 68 by a sealing spring 70. A pair of pressure feed back chambers71, 71' is provided at both sides of the pressure controlling springchamber 63, and the pressure of the gas consuming system 51 iscommunicated with the feed back chambers 71 via openings 72. An O ring73 seals between the gas outlet 66 and the pressure feed back chamber71, and an O-ring 74 seals the gas inlet 65 from the atmosphere. Anotherpressure controlling valve mechanism for the other gas flowing systems52 and 56 is constructed in the same manner; and "dash" marks areapplied on each corresponding member of the pressure controlling valvemechanism for the gas systems 51 and 55. Numeral 75 indicates hole forintroducing atmospheric pressure or other suitable pressure to thepressure controlling spring chamber 63.

The pressure controlling valve means 50 thus formed is operated asdescribed below. Gasses supplied from the gas supplying systems 55 and56 flow through the gas inlets 65, 65', respectively, into the casing61, and, where the valves 67, 67' are opened, are supplied through theopening 68' and the gas outlets 66, 66' to the gas consuming systems 51,52 respectively. The pressure in the gas consumming systems 51 and 52change with the gas supplying amounts, but are introduced into thepressure feed back chambers 71 and 71' and controlled therein in amanner hereinafter described.

Neglecting the friction forces of the O-ring 73, 74, 73', 74' anddiaphragm 62, 62', as the diameter of the O-ring 73 or 74 is equal tothat of the O-ring 73' or 74' to offset the thrust of the gas supplyingside with that of the gas consuming side, the force compressing thevalve rod 69, 69' into the sealing spring 70, 70' is the sum of a forcecaused by multiplying the inner pressure of the pressure controllingspring chamber 63 by the effective area of the diaphragms 62, 62' and arepelling force of the pressure controlling spring 64. On the otherhand, the inverse force is the sum of a force caused by multiplying theinner pressure of the pressure feed back chamber 71, 71' by theeffective area of the openings 72, 72' and repelling forces of thesealing springs 70, 70'. The difference between both said forces servesas a force to thrust the valve rod 69 towards the sealing spring 70,i.e., a force to open the valve 67. Accordingly, the pressure in the gasconsumming system is determined by the force which actuates the valverod, or the repelling force of the pressure controlling spring 64.According to the pressure controlling mechanism of this invention, apair of pressure controlling means, each having the same size andstructure, is arranged symmetrically but mutually united, and a singlepressure controlling spring means is used to actuate automatically therepelling force to the diaphragms of both gas supplying and consumingsystems. Besides, the pressures in two gas consuming systems arecontrolled to show the equal value by the pressure controlling mechanismwithout using other special means.

In order to make controllable the pressure range of the gas consumingsystem, the repelling force of the pressure controlling spring may bemade variable, as shown in the FIG. 10.

The FIG. 10 shows a structure of the pressure controlling spring chamber63 in the FIG. 9, in which a means for adjusting the preset pressure bychanging the compressed length of the spring is provided. The repellingforce of the spring will be changed in accordance with the compressedlength of the spring. The pressure controlling spring in this example iscomposed of two springs 75 and 76, the former of which is providedbetween the diaphragm 62 and the spring seat 77 and the latter of whichis provided between the other diaphragm 62 and the spring seat 78. Eachof said spring seats 77, 78 is supported so as to move axially along apair of guide pins 79, 80, respectively. A repelling force adjustingmeans 81 comprises a bolt 82 screwed into the spring seat 77, a bolt 83the hand of the thread of which is the reverse of the hand of the threadon bolt 82 screwed into the spring seat 78, and a flange like dial 84fixedly connected to the bolts 82, 83 at the middle part. A handlingopening 85, usually closed by the lid 86, is provided on the casing 61.The guide pins 79, 80 are attached to the valve casing 61.

When the repelling forces of the pressure controlling spring 75, 76 arerequired to be changed, the handling dial 84 will be rotated to shiftthe spring seats 77, 78 axially and relatively as the rotation of therod spring seats is prevented by the guide pins 79, 80. Because thethreads on the bolts 82 and 83 are of opposite hand, the spring seats77, 78 move in opposite directions when the handling dial 84 is turned.Thus, the repelling forces of the pressure controlling springs 75, 76can be changed.

As particularly described above, according to the single pressureadjusting valve means of this invention, the pressures of the hydrogengas and oxygen gas systems can be adjusted to an equal value, and alsoset easily and simultaneously to the desired value.

While this invention has been described with reference to particularembodiments thereof, it will be understood that the numerousmodifications may be made by those skilled in the art without actuallydeparting from the scope of the invention.

Therefore, the appended claims are intended to cover all such equivalentvariations as coming within the true spirit and scope of the invention.

What is claimed is:
 1. In a fuel cell comprising:1. a generator cellhaving a fuel gas chamber, an oxidizing gas chamber, and anelectrolyzing solution chamber;
 2. a fuel gas circulating circuit forsupplying fuel gas to the fuel gas chamber of said generator cell;
 3. anoxidizing gas circulating circuit for supplying oxidizing gas to theoxidizing gas chamber of said generator cell;
 4. an electrolytecirculating circuit for supplying an electrolytic solution to theelectrolyzing solution chamber of said generator cell;
 5. a gas coolerlocated in said fuel gas circulating circuit beneath said generatorcell;
 6. a formed water tank located beneath said gas cooler and influid communication therewith, whereby moisture formed in saidgenerating cell, carried by said fuel gas into said gas cooler, andcondensed therein will drip by force of gravity into said formed watertank;
 7. an electrolyzing solution tank located in said electrolytecirculating circuit above said generator cell; and
 8. a clean water tanklocated above said electrolyzing solution tank and in fluidcommunication therewith, whereby clean water can be supplied by force ofgravity from time to time to said electrolyzing solution tank from saidclean water tank in order to control the concentration of theelectrolytic solution therein,whereby gas leaked into the electrolyzingsolution chamber of said generator cell is carried by the electrolyticsolution flowing through said electrolyte circulating circuit upwardsinto said electrolyzing solution tank, where it is easily separated fromthe electrolytic solution, and electrolytic solution leaked into thefuel gas chamber of said generator cell is carried by the fuel gasflowing through said fuel gas circulating circuit downwards into saidgas cooler, where it is separated from the fuel gas and dripped intosaid formed water tank, the improvement comprising means for keeping thefuel gas pressure in the fuel gas chamber of said generator cell and theoxidizing gas pressure in the oxidizing gas chamber of said generatorcell constant and equal.
 2. A fuel cell as claimed in claim 1 whereinsaid means for keeping the fuel gas pressure in the fuel gas chamber ofsaid generator cell and the oxidizing gas pressure in the oxidizing gaschamber of said generator cell constant and equal comprise:a. a firstdiaphragm forming a portion of the wall of said fuel gas chamber; b. asecond diaphragm forming a portion of the wall of said oxidizing gaschamber; c. a first compression spring having a first end thereofbearing against said first diaphragm; d. a second compression springhaving a first end thereof bearing against said second diaphragm, saidsecond compression spring being coaxial with said first compressionspring; e. a first spring seat bearing against the second end of saidfirst compression spring; f. a second spring seat bearing against thesecond end of said second compression spring; g. means for allowing saidfirst and second spring seats to translate towards and away from saidfirst and second diaphrams but preventing said first and second springseats from rotating about the axis of said first and second compressionsprings; and h. an adjusting means comprising a first bolt threadedlymounted in said first spring seat and a second bolt threadedly mountedin said second spring seat, the hands of the threads on said first andsecond bolts being opposite,whereby when said adjusting means is rotatedin one direction, said first and second spring seats are moved towardssaid fuel gas chamber and said oxidizing gas chamber, respectively, and,when said adjusting means is rotated in the opposite direction, saidfirst and second spring seats are moved away from said fuel gas chamberand said oxidizing gas chamber, respectively.